Preform design with increased materials utilization and processing map analysis for aluminum hot forging process

Abstract

In this article the conventional aluminum hot crown forging process for mass production of shock absorber assembly is experimentally and numerically studied. The preform design method was proposed to improve the quality of post-forged product, save the material weight, and decrease manufacturing cost for finishing process. Finite element (FE) simulation software was employed to numerically analyze the material flow lines, strain, temperature, and effective stress distribution to reduce time and cost in obtaining the appropriate preform design. Furthermore, the software is used to extract the numerical results of power dissipation efficiency and instability from the processing map analysis of stress-strain rate material data in different temperature and strain conditions, which are useful parameters to analyze formability and microstructures of material. Then, the improved hot forging design was achieved by the combined-analysis of preforming design, material utilization, and processing map. The numerical results have accurately predicted the poor quality and serious underfilling defects in the conventional post-forged product, and finally the improved design have successfully diminished defects, met precision tolerances and satisfied quality requirements. The proposed design saves material weight up to 10.26 %, increases material utilization from 79.01 % to 88.08 % which improves the problem of excessive flash in the conventional case, and reduces the forging load up to 12.40 % which benefit the dies life. Two intriguing areas were microstructurally examined and the results showed that the grain sizes are adequately fine to satisfy the expected mechanical properties.